The embodiments herein relate generally to equipment utilized during subterranean formation operations and, more particularly, to a polymer composite wireline cable comprising optical fiber sensors and associated methods.
Downhole tools used in well operations may be deployed into, and retrieved from a subterranean formation (e.g., a wellbore therein) using a cable, such as a wireline cable. As used herein, the term “wireline” refers to single-strand or multi-strand wire or cable and may also contain electrical conductors or other electrical components, commonly used in oil or gas operations. For example, wireline cables may be employed to perform well logging operations to gather petrophysical, geophysical, and well production information for a particular subterranean formation. Such wireline cables are required to have sufficient tensile capability to support the weight of the tool and the wireline itself. Accordingly, performance of the wireline cable is particularly important to ensure successful placement or use of the downhole tool.
Characteristics of traditional wireline cables themselves and/or the conditions of a subterranean formation environment may increase the likelihood that such cables fail. For example, wellbore depth, temperatures in excess of 150° C., and extreme pressures may increase strain on the cable, encourage wellbore fluids (e.g., hydrocarbon fluids or gases) to penetrate the cable matrix, and the like, causing delamination or crack-based structural defects in the cable. Moreover, catastrophic failure will occur when the effective loading capability is lower than the applied loading tensile strain.
Wireline cables are often reused and monitoring the integrity of a wireline cable may be particularly difficult due to, among other things, the great length of a wireline. Accordingly, traditional integrity determinations that involve non-destructive inspections may include laser ultrasonic, thermography, microwave, terahertz, RF, eddy current, and/or x-ray radiography techniques. These non-destructive inspections may only analyze the cable surface defects, or result in only a representative portion of the cable being evaluated and not the entire length of the cable (e.g., only single-point non-destructive inspection), absent scanning of the entire length thereof. That is, traditional mechanical fatigue evaluations do not quantitatively evaluate such fatigue against defect number, size, orientation, and the like, for the full length of the cable. Furthermore, traditional non-destructive inspections are more adequate in laboratory settings, rather than in field use.